In recent years, transparent conductive films have been indispensable when manufacturing photoelectric converters, such as solar cells and the like. As a known transparent conductive film, an ITO film (a tin-doped indium oxide film) is known. The ITO film has the advantages of excellent transparency and low resistance.
Meanwhile, there has been a need for cost reduction in solar cells or liquid crystal displays. However, since indium is expensive, when the ITO film is used as a transparent conductive film, there is a disadvantage in that the solar cell also inevitably becomes expensive. In the case of manufacturing solar cells or the like, an amorphous silicon film is formed on a transparent conductive film by a plasma CVD method or the like. At this time, if the transparent conductive film is an ITO film, there is a problem in that hydrogen plasma at the time of plasma CVD leads to deterioration of the ITO film.
In order to solve such problems, it has been proposed that a zinc oxide-based film doped with a conductive active element, such as Al, B, Si, Ga, or Sc, which can be prepared at low cost is used as a transparent conductive film for solar cells or the like, and a zinc oxide-based sputtering target is used to form the zinc oxide-based film by sputtering (for example, Patent Document 1). According to this zinc oxide-based sputtering target, an extremely low resistance zinc oxide-based sintered body is obtained by containing a predetermined amount of the conductive active element in zinc. Sintering density and conductivity of the sintered body are improved if the raw powder is fine and has high dispersibility.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 6-2130.